Implemented CN-Heavy algo, Algo tests and fixed n-loop variants (#86)

* Debouncing of connection retry when connecting donation server fails
* When PoW variant is set on proxy, it will overrule local set PoW
* Implementation of cn_heavy algo
* Added self test for cn-heavy
* Fixed n-loop variant of powV2 and cn-heavy
* Fixed n-loop variant of powV2 and added cn-heavy for ARM
* Fixing n-loop for arm
* Limited cn-heavy to max hashfactor 3 on higher seltest fails.
* Removed a lot of casts
* Fixed algo selftest

src/crypto/CryptoNight.h

@@ -32,6 +32,7 @@
 
 #define MEMORY      2097152 /* 2 MiB */
 #define MEMORY_LITE 1048576 /* 1 MiB */
+#define MEMORY_HEAVY 4194304 /* 4 MiB */
 
 struct cryptonight_ctx {
     alignas(16) uint8_t state[MAX_NUM_HASH_BLOCKS][208]; // 208 instead of 200 to maintain aligned to 16 byte boundaries